1. Field of the Invention
The instant disclosure relates to a method and apparatus for fabricating two-dimensional layered chalcogenide film; in particular, to a chemical vapor deposition method and an apparatus for fabricating two-dimensional layered chalcogenide film.
2. Description of Related Art
Monolayer metal chalcogenides, specifically two-dimensional transition metal dichalcogenides, TMDs, have recently captured enormous attention in the field of optoelectronics, valleytronics, and spintronic since the discovery that monolayer semiconducting TMDs exhibit a direct bandgap, inviting novel manipulations of chemical, physical, and electrical properties of the transition metal dichalcogenides.
In the current fabrication of metal dichalcogenide films, chemical vapor deposition (CVD) at high temperature is usually required. Taking the formation of molybdenum disulfide (MoS2) as an example, US application 2014/0251204 discloses that the reaction of MoO3 vulcanization occurs at a temperature ranging from 800 to 1000° C. to form MoS2 on a substrate.
However, during the high temperature CVD process, a substantial amount of chalcogens which have a relatively lower melting point compared to the transition metals tends to sublimate at such a high temperature. Thus, the chalcogens of the metal-based chalcogenide film might be lost. In addition, the evaporation of the chalcogens may result in a substantial amount of vacancies in the deposited metal-based chalcogenide film, which, in turn, affects the physical properties of the resulting metal-based chalcogenide film. Accordingly, the development of the low-temperature process to fabricate large-area and high-quality metal-based chalcogenide film has become a critical technique.